Evaporating Diesel Spray Visualization using a Double-pass Shadowgraphy/Schlieren imaging

Pastor, Javier; García, José Manuel Sánchez; Pastor, José Manuel; Zapata, L. Daniel

doi:10.4271/2007-24-0026

Cited by 27 publications

(19 citation statements)

References 23 publications

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“…The typically observed disturbances result from temperature gradients in the boundary layer at the windows [47]. This becomes more severe in experiments at higher density and ambient temperature, as reported in other studies [15,29,46]. The background disturbances at a given temperature increase with density for mainly two reasons: 1) the differences in density between the fuel and the ambient are reduced and 2) the background structures themselves appear confined to smaller scales.…”

Section: Experimental Vapor Penetrationsupporting

confidence: 48%

“…However, the projected pixel size in this case was increased to 0.22 mm/pixel due to the optical arrangement. Previous spray related studies show largely different arrangements to capture the Schlieren effects, mostly based on experience, desired sensitivity and experimental conditions [22,23,29,30]. In this work, a 3-mm circular aperture was placed close to the LED to limit the size of the light source.…”

Section: High-speed Schlieren Imagingmentioning

confidence: 99%

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Experimental and Numerical Analyses of Liquid and Spray Penetration under Heavy-Duty Diesel Engine Conditions

Maes

Dam

Somers

et al. 2016

SAE Int. J. Fuels Lubr.

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The modeling of fuel sprays under well-characterized conditions relevant for heavy-duty Diesel engine applications, allows for detailed analyses of individual phenomena aimed at improving emission formation and fuel consumption. However, the complexity of a reacting fuel spray under heavy-duty conditions currently prohibits direct simulation. Using a systematic approach, we extrapolate available spray models to the desired conditions without inclusion of chemical reactions. For validation, experimental techniques are utilized to characterize inert sprays of n-dodecane in a high-pressure, high-temperature (900 K) constant volume vessel with full optical access. The liquid fuel spray is studied using high-speed diffused back-illumination for conditions with different densities (22.8 and 40 kg/m 3 ) and injection pressures (150, 80 and 160 MPa), using a 0.205-mm orifice diameter nozzle. High-speed Schlieren imaging is used to analyze the influence of these boundary conditions on the spray penetration. Simulations of the fuel spray are performed using a dedicated computational mesh with refinements at the known location of the jet to capture the smallest scales of interest. Using a blob injection model refined with a primary atomization and secondary breakup model, correct trends and good agreement are achieved for both liquid and spray penetration. The capability of capturing the trends at largely varying boundary conditions with a single computational approach provides a solid base for future work.

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Section: Experimental Vapor Penetrationsupporting

confidence: 48%

Section: High-speed Schlieren Imagingmentioning

confidence: 99%

Experimental and Numerical Analyses of Liquid and Spray Penetration under Heavy-Duty Diesel Engine Conditions

Maes

Dam

Somers

et al. 2016

SAE Int. J. Fuels Lubr.

View full text Add to dashboard Cite

show abstract

“…Background illumination intensity was calibrated to achieve the same levels before starting the experiments campaign. Additionally, reflections, or double-imaging, were filtered in the cut-off plane, due to a similar phenomenon as reported by Pastor et al [11]. Optical accesses typically present small misalignments, caused by differences in the stress of the sealing gaskets, facility assembly, among others, which turn difficult to control.…”

Section: Further Analysis Of the Two Schlieren Configurationsmentioning

confidence: 99%

“…It is not only fundamental knowledge to understand how boundary conditions affect these variables, but the experimental data is necessary to validate computational tools, such as 1-D models or computational fluid dynamics (CFD). The two most common Schlieren configurations are single-pass (SP) [2,[5][6][7][8][9] and double-pass (DP) [3,[10][11][12][13]. Typically, the first setup is used for axially drilled single-orifice nozzles, where vessels with multiple optical accesses allow line of sight visualization.…”

Section: Introductionmentioning

confidence: 99%

Vapor phase penetration measurements with both single and double-pass Schlieren for the same injection event

Payri

Salvador

Viera

2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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Schlieren imaging has been adopted as a standard optical technique for the analysis of diesel sprays under engine like conditions. A single-pass Schlieren arrangement is typically used for the study of single-orifice nozzles, as vessels with multiple optical accesses regularly allow line of sight visualization. Contrarily, for multi-spray nozzles, measurements are commonly performed through a single optical access, in which case a double-pass arrangement is employed. As a consequence, the light beams pass through the test section twice, increasing the optical sensitivity of the Schlieren setup. However, the impact this has on the macroscopic spray characteristics is still unclear. The scope of this study is to analyze the differences in vapor phase penetration for the same injection event, through high-speed imaging, for both single and double-pass Schlieren configurations. Experiments were carried out with a three hole nozzle with a nominal orifice diameter of 90 µm, named Spray B from the Engine Combustion Network, using commercially available diesel fuel and in non-reactive conditions. The impact of different injection pressures and chamber densities on the spray captured by each setup was assessed. On the results, vapor phase penetration followed the expected trend found in the literature, as it increases with increasing injection pressure and decreasing chamber density. Comparing the optical setups, vapor phase penetration obtained with the double-pass arrangement was marginally higher. The deviation was observed throughout all tested conditions. Although the discrepancy was approximately constant for different injection pressures and chamber temperature, it increased with increasing density. These results highlight the importance of a proper understanding regarding the limitations of optical diagnostics, in particular for results used in calibration of computational models.

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“…Lee). atomization and spray characteristics, the visualization studies of fuel spray by imaging scheme have been widely investigated by many researchers [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Application of background oriented Schlieren (BOS) method for visualization of evaporating impinged spray

Bang

Lee

2015

Optik

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Evaporating Diesel Spray Visualization using a Double-pass Shadowgraphy/Schlieren imaging

Cited by 27 publications

References 23 publications

Experimental and Numerical Analyses of Liquid and Spray Penetration under Heavy-Duty Diesel Engine Conditions

Experimental and Numerical Analyses of Liquid and Spray Penetration under Heavy-Duty Diesel Engine Conditions

Vapor phase penetration measurements with both single and double-pass Schlieren for the same injection event

Application of background oriented Schlieren (BOS) method for visualization of evaporating impinged spray

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